How to properly flush your 1992 or 1993 Polaris PWC

The purpose of this is to make clear how to flush the engine of your 1992 SL650 or 1993 SL650/750.

the cooling system of these craft was not very well designed. the 1992 has a bulletin to update the cooling system to match the one in the 1993 models. unfortunately, the 1993 models were not much better. for 1994 and beyond, the entire cooling system was redesigned.

I wanted to pass along this information that was not spelled out anywhere that I could find for future readers...I myself only figured out how all this worked after having owned this craft for 5 months, and discovering a nice surprise in my engine. namely, sand. lots of it.

first, do yourself a favor and buy the reverse flushing kit, part number 2871034. I picked it up for $8 on ebay. you will thank yourself later for getting this. in fact, this should be mandatory, you will need it.

the water flushing for the 1992-1993 fuji engines happens from the bottom of the engine using the supplied flush hose connector that you will see laying next to the coupler/through hull bearing area.

it is very important that you flush and drain the engine after every ride. sand will and does collect at the bottom of the water passages in the engine, to the point where you will no longer be able to flush or drain it, and consequently, will no longer properly cool the engine.

if for some reason your cooling system does become packed with sand and cannot be flushed the normal way, you will need to remove the cooling hoses from the bottom of the crankcase. this involves removing the exhaust system via the exhaust manifold to get to them, which took me 2 hours to do the first time. the hoses have to be removed due to the angles of the hoses not being conducive to getting sand out.

K447 Note: Do not pressurize the engine water jackets if the exhaust manifold and exhaust pipe are not installed.
If you run the engine with the exhaust system not installed you will spew oily exhaust into the hull.

Once this is done, attach a garden hose to the flushing kit mentioned above (you did buy this, right?) and say a prayer to the deity of your choice. you hopefully should be able to flush out the water cooling system that way. this can and will be messy. make sure your engine is running before you turn on the water (and the water is turned off before shutting off the engine)!

if you are still unable to properly flush the engine, you will have to remove the cylinders to manually clean out the water jackets. if you do not do this, you eventually will blow a head gasket and/or worse due to insufficient cooling of your engine. I know, because this happened to me. make absolutely sure you protect the insides of your engine while doing this, we do not want sand inside the engine! I find the best way to help with this is when removing the cylinder, put that piston to as low as you can, that way you can blow out the sand that is trying to get into the crankcase. bad sand, BAD!

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the manual says to drain the engine by removing the flush hose cap and tipping the craft ccw, but this cannot possibly get the sand and water out due to the angles involved with the cooling hoses attached to the bottom of the engine. personally, I attach a hose to the flush hose for a minute, then attach it to the reverse flusher and run the water until it's coming out clear from the bottom, blip the throttle a few times for no reason other than it sounds awesome, then call it a day. during the winter, I pour a small amount of RV antifreeze into both the flushing kit and the flush hose. there is no way to get all of the water out of the engine unless you want to pick up the craft and shake it out.

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for me, the consequence of not flushing was that sand completely filled the pto cylinder water passages, which meant that piston was not getting adequate cooling. this in turn blew the head gasket, and allowed water and sand into the pto cylinder and crankcase. not good. not good at all. I am passing on my ignorance (and subsequent learning) in the hopes that you do not have to repeat what I went through to fix it.

so the moral of this post is:

Flush and drain your 1992-1993 Polaris Fuji watercraft engine every time you use it, or else!

your mileage may vary...I am not an expert on watercrafts, please double check this information before you use it. I am merely presenting information as I see it, in the hopes that this may help others.

that is a nice way to make the process of water flow in the bottom flush tube of the 650 easier which I am going to copy for sure...but just to clarify for others this not a replacement to the reverse flush kit I had described in the writeup.

How do I flush the fresh water intake grate ? Looks like it is clogged and I'm getting a over heat light after running.

There should be a small postage stamp sized plastic grate inside the jet pump nozzle on the right side facing the rear of the ski. Check that for clogs. You can also reverse flush the ski from the water bar opposite the temp sensor with a flush kit.